What do you think you know about astronomy? For example, what causes us to have seasons? If you said that it’s our distance from the sun – sorry, you’re wrong. Or how about why the sky is blue? If you think it’s that the sky reflects the sea, nope. Wrong again. Or perhaps you think that the moon’s tidal effect makes people crazy, or that an egg can only stand on end if it’s the Vernal Equinox or that an alignment of the planets will cause a terrible buildup of gravity that will kill us all!

All wrong. But you would not be alone. For a society as technologically advance as ours (and if you’re reading this, then chances are good that you live in a technologically advanced society), the general public has a big problem with science. People see it as being too hard to understand, or too removed from their daily lives. Politicians bemoan the fact that American schoolchildren are falling behind in science, but science funding is almost always on the list of cuts that can be made to save money. We love technology, but hate science, and that is a path to certain doom.

Of all the sciences, though, astronomy is perhaps the worst understood. A lot of people still confuse it with astrology, which is probably a huge part of the problem right there. For millennia, we have thought about the planets and stars as celestial things, unknown and unknowable by such base creatures as ourselves. It’s only in the last hundred years or so that we’ve been able to rapidly improve our understanding of the universe, and popular knowledge hasn’t caught up with that yet.

And so bad misconceptions of astronomy persist in the public imagination.

Fortunately, we have people like Phil Plait to set the record straight, and that is indeed what he does in this book.

While there are many educators out there who believe that a wrong idea, once implanted, is impossible to eradicate, Plait sees it as a teachable opportunity. Take, for example, the commonly held belief that on the Vernal Equinox – and only on the Vernal Equinox – you can balance an egg on its end. Many people believe this, and it’s an experiment that’s carried out in classrooms around the country every March. Teachers tell their students, and the local news media tell their viewers, but no one stops to ask Why. Why would this day, of all the days in the year, be so special? More importantly, how can we test that assertion?

Fortunately, that’s within the powers of any thinking individual, and it should be the first thing teachers do once they’ve finished having fun balancing eggs: try and do it again the next day. If you can balance an egg on April 3rd, or May 22nd or August 30th, or September 4th or any other day of the year, then you have successfully proven the Equinox Egg Hypothesis wrong. Congratulations! You’re doing science!!

Or perhaps you’ve heard the story that you can see stars from the bottom of a well, or a tall smokestack. This is because, the idea goes, the restricted amount of light will not wash out the stars so much, giving you a chance to do some daytime astronomy. Well, there’s an easy way to test this one too, if you have an old factory or something of that nature nearby. What you’ll discover is that no matter how much you try to restrict your view of the sky, it’ll still be washed out and you won’t see any stars at all.

One more good one that a lot of people believe – the moon is larger in the sky when it’s near the horizon than when it’s at its zenith. Again, this is something that’s very easy to test. Go out as the full moon is rising, looming large in the sky, and hold up an object at arm’s length – a pencil is usually recommended. Make a note of the moon’s apparent size as compared to the eraser. Then go out again when the moon is high in the sky and repeat your observation. The moon appears to be the same size, no matter how it may look to you.

Of course, there’s a lot of science into why these things are the way they are. The chicken egg thing is because there’s no singular force that is only acting on chicken eggs and only doing so on one day of the year (which is not even universally regarded as the first day of spring). As for the inability to see stars in the daytime, that’s because our pesky atmosphere scatters a lot of the light coming from the sun, so light appears to come from everywhere in the sky. The only thing you’re likely to see in a blue sky is the moon, and MAYBE Venus, if you’re really sharp-eyed and lucky.

The Moon Illusion is not well-understood, actually. It’s probably not the brain comparing the moon with objects on the horizon – the effect works at sea, too. It’s probably a combination of competing psychological effects that deal with distance, none of which can accurately deal with how far away the moon is.

Regardless, all of these things are easily testable by anyone. The problem is that so few people take that extra time to actually test them, or even think that they should.

There are some myths and misconceptions that take a little more expertise to explain, such as why tides and eclipses happen, how seasons occur and why the moon goes through phases. But these explanations aren’t very difficult and are well within the understanding of any intelligent adult. Unfortunately, there are a lot of myths that are stubborn, entrenched into the heads of people everywhere and very hard to get out. Not the least of these are the beliefs that UFOs are alien spacecraft and that we never went to the Moon.

Interestingly enough, both of these rest on the same basic problem: we can’t rely on our own brains to accurately interpret the data that we see. Plait recounts a story where he was mesmerized by some strange lights in the night sky while watching a 3 AM shuttle launch. They seemed to hover in place, making strange noises, and it wasn’t until they got much closer that he was able to see them for what they were: a group of ducks that were reflecting spotlights off their feathers.

Our brains believe things, and interpret the observations to fit those beliefs. So when the dust on the moon doesn’t behave the way we expect dust to behave, some people believe that to be evidence of fraud, rather than the natural behavior of dust on the moon. We are creatures of story, which is why we like conspiracy theories and astrology. We want the world to make a kind of narrative sense, so often the first explanation we come up with is a story that sounds good. Unfortunately, just because the story sounds good, that doesn’t make it true.

He also takes a swipe at bad movie science, but in a good-natured manner. Even he admits that movies are more likely to favor story over science, but there are some common errors that make it into so many science fiction films – sound in space, people dodging lasers, deadly asteroid fields – these things may be dramatically interesting, but they’re all bad science. And while it would be annoying and pedantic to pick out every example of how the rules are bent for sci-fi (“Please. Why would the aliens come all the way to Earth to steal water when it exists in abundance out in the Kuiper Belt? I scoff at your attempt!”), they do offer an excellent opportunity to teach people about how science works.

One of the things I’ve always liked about Plait is his obvious enthusiasm for not just astronomy but for science in general. Here we have this excellent system to cut through the lies our brains tell us and get closer to knowing what’s actually going on. Science forces us to question our assumptions, look at things from many points of view, and arrive at a conclusion that best describes the phenomenon we’re observing. When Plait talks about science, he is not condescending or dry or super-intellectual, the way so many people imagine scientists to be. He’s excited that he gets to use this amazing tool for understanding the universe, and he wants other people to use it.

If you’re an astronomy buff, like myself, you probably won’t learn much new information from this book. But hopefully you’ll be re-invigorated to go out there and look at the world through a scientific, skeptical eye, and you’ll be willing to confront these misconceptions when next you come across them. Even better, you might start thinking about what else you think you know, and how you can go about testing it.

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“If a little kid ever asks you just why the sky is blue, you look him or her right in the eye and say, ‘It’s because of quantum effects involving Rayleigh scattering combined with a lack of violet photon receptors in our retinae.'”
– Phil Plait, Bad Astronomy
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